What Is Pentaerythritol/Terephthalic Acid Copolymer?
Pentaerythritol/Terephthalic Acid Copolymer is a polyester formed by the polycondensation of pentaerythritol (a tetrol) with terephthalic acid (a dicarboxylic acid). In cosmetics, it is used as a film former that provides durable, flexible coatings on skin, lashes, and hair. It is related to PET (polyethylene terephthalate) chemistry but formulated as a cosmetic-grade, lower-MW polymer for application-specific properties.
Key Skin Benefits
+ Durable film formation — long-lasting hold on skin and hair
+ Flexible — resists cracking and flaking better than rigid polymers
+ Water resistance — helps products withstand moisture and humidity
+ High gloss — contributes to shine in nail and hair products
Pros
+ Excellent durability for long-wear products
+ Flexible film — comfortable wear without stiffness
+ Good compatibility with pigments and fillers
+ Effective at low concentrations
Cons
− Fully synthetic — not suitable for natural formulations